Neil Young is just finishing a 32 date tour. Springsteen, Jagger and Dylan are still doing extensive tours. The difference is that they stay in shape and eat right.
If Jackson lived a cleaner life he could have done it. Maybe not the extensive dance routines, but he could have adapted if he were healthy.
If the reports are true about the drugs, he seems to have taken the same path as Elvis and/or Howard Hughes.
As long as your cardio system is healthy, a big bag of coke makes anything possible.